Description: (Applicant's Description) In this project we will test the concept of vaccination against a cell surface antigen expressed on normal as well as malignant B lymphocytes. We have chosen the CD20 molecule as the target of this effort because of its universal expression on Non Hodgkin's Lymphoma and because of our clinical success with passive antibody therapy against this molecule. We know from our work that B-cell depletion from passive antibody therapy in humans does not result in immunosuppression and from the work of others in knockout mice that the CD20 molecule is dispensable. The critical questions addressed by this proposal are therefore, can an immune response be induced against this autoantigen? If so, will such a response be deleterious to the host? And will an immune response against CD20 protect against the growth of B-cell lymphomas? The vaccine strategies will employ molecular constructs of the CD20 molecule both full length and the hydrophilic portions linked as fusion proteins to the cytosine Granulocyte Macrophage Colony Stimulating Factor, (G-CSF). These molecules will be presented to the immune system by Dendritic Cells (DC). In addition adenovirus (AdV) vectors will be constructed which express the CD20 molecule and these viruses will be tested as vaccines and as vectors for the delivery of the CD20 gene into dendritic cells.